Due to the increasing energy demands, offshore oil and gas production is moving into deeper waters. For providing an efficient and secure production, processing facilities are being installed at the ocean floor. Such subsea installations may include a range of components, including pumps, compressors and the like, as well as a power grid for operating the components. The power grid may, for example, include a subsea transformer, subsea switchgear and subsea variable speed drives. The components of the subsea installation are to be protected from the surrounding seawater, in which pressures of 300 bar or more may prevail (e.g., at installation depths of 3,000 m or more).
Components of such subsea installations may include electronic equipment that may be monitored and/or controlled from a topside installation, such as a topside control system that may be located on a fixed or floating vessel (e.g., a ship or a platform) or may be based onshore. The subsea installation may, for example, include one or more subsea control modules (SCM) that may receive commands from the topside installation or may transmit information to the topside installation. The one or more SCMs may communicate with each other or may interface a sensor.
In such systems, communication links may be provided between the sensors and the subsea control modules, as well as between the subsea control modules and a topside installation. Communication may, for example, be implemented by a network communication (e.g., Ethernet). Although such type of communication link may achieve relatively high bandwidth (e.g., 10 Mbps, 100 Mbps or even 1 Gbps), such types of communication links are limited in physical length. As an example, Ethernet based on a twisted copper wire pair has a limited length of about 100 m according to Ethernet standards. Enhanced solutions may achieve distances exceeding 150 meters length of the communication link. In general, communication using such type of technology is thus limited to subsea control modules of the same Christmas tree. A communication between different Christmas trees may not be provided, as each installation uses their own link to a topside installation via an umbilical or the like.
Also, it is desirable to retrieve modules from a subsea installation or to install new modules or to exchange modules. Consequently, subsea equipment may be connected and disconnected from power and communication links. For this purpose, wet mateable connectors may be provided. Such connectors are relatively complex and cost intensive to design and produce.
It is desirable to extend the distance over which subsea communication may occur, while maintaining a high bandwidth. For example, it is desirable to enable communication between different Christmas trees. At the same time, it is desirable to keep system complexity relatively low and to limit the complexity that is added to the system. Also, such communication links are to be connectable and disconnectable under water while keeping maintenance low and reliability high.